// boards/smartresponsexe/board.c
#include "snek.h"
#include "bb_lcd.h"
#include "bb_keyboard.h"
#include <string.h>
#include <stdbool.h>
#include <avr/io.h>
#include <avr/interrupt.h>
#include <stdint.h>

#define LCD_COLS 40
#define LCD_ROWS 20
#define INPUT_BUFFER_SIZE 128

static uint8_t cursor_x = 0;
static uint8_t cursor_y = 0;
static char input_buffer[INPUT_BUFFER_SIZE];
static uint8_t input_pos = 0;
static uint8_t cursor_pos = 0;
static int scroll_offset = 0;
static bool cursor_visible = true;
static uint32_t last_cursor_toggle = 0;

volatile uint32_t _millis = 0;

uint32_t board_millis(void) {
    uint32_t m;
    cli();
    m = _millis;
    sei();
    return m;
}

ISR(TIMER0_COMPA_vect) {
    _millis++;
}

void timer0_init(void) {
    TCCR0A = (1 << WGM01);
    TCCR0B = (1 << CS01) | (1 << CS00);
    OCR0A = 249;
    TIMSK0 = (1 << OCIE0A);
}

void scroll_up(void) {
    lcdScrollUp();
    cursor_y--;
    if (scroll_offset < LCD_ROWS - 1) scroll_offset++;
}

void scroll_down(void) {
    if (scroll_offset > 0) scroll_offset--;
}

void board_init(void) {
    lcdFill(0);
    lcdDisplay();

    // Display memory info
    extern uint8_t __heap_start, *__brkval;
    uint16_t free_memory = (uint16_t)&__heap_start - (uint16_t)(__brkval == 0 ? &__heap_start : __brkval);
    char mem_line[40];
    snprintf(mem_line, sizeof(mem_line), "Free RAM: %u bytes
", free_memory);
    for (char *p = mem_line; *p; p++) putchar(*p);

    // Display SRXE-Snek splash
    const char *splash[] = {
"                  _                                 ",
"                 | |                                ",
"  ___ ____  _____| |  _ _____ ___  ____ _   _ _____ ",
" /___)  _ \| ___ | |_/ |_____)___)/ ___| \ / ) ___ |",
"|___ | | | | ____|  _ (     |___ | |    ) X (| ____|",
"(___/|_| |_|_____)_| \_)    (___/|_|   (_/ \_)_____)",
        NULL
    };
    for (int i = 0; splash[i] != NULL; i++) {
        for (const char *p = splash[i]; *p; p++) putchar(*p);
        putchar('
');
    }

    // Show Snek version banner
    extern const char *snek_version;
    for (const char *p = snek_version; *p; p++) putchar(*p);
    putchar('
');

    timer0_init();
    sei();
    lcdInit();
    kbdInit();
    lcdFill(0);
    lcdDisplay();
    cursor_x = 0;
    cursor_y = 0;
    input_pos = 0;
    cursor_pos = 0;
    scroll_offset = 0;
    cursor_visible = true;
    last_cursor_toggle = board_millis();
    memset(input_buffer, 0, sizeof(input_buffer));
}

void display_prompt(void) {
    putchar('>');
    putchar(' ');
}

void redraw_input_line(void) {
    lcdSetCursor(0, cursor_y * 8);
    for (int i = 0; i < LCD_COLS; i++) putchar(' ');
    cursor_x = 0;
    lcdSetCursor(0, cursor_y * 8);
    // Wait for key before prompt
    while (!keyboard_read());
    display_prompt();
    for (uint8_t i = 0; i < input_pos; i++) {
        putchar(input_buffer[i]);
    }
    lcdSetCursor((2 + cursor_pos) * 6, cursor_y * 8);
    if (cursor_visible) {
        lcdWriteChar('_');
    } else {
        lcdWriteChar(' ');
    }
    lcdDisplay();
}

void insert_char(char c) {
    if (input_pos >= INPUT_BUFFER_SIZE - 1) return;
    for (int i = input_pos; i > cursor_pos; i--) {
        input_buffer[i] = input_buffer[i - 1];
    }
    input_buffer[cursor_pos++] = c;
    input_pos++;
    redraw_input_line();
}

void delete_char(void) {
    if (cursor_pos == 0) return;
    for (int i = cursor_pos - 1; i < input_pos - 1; i++) {
        input_buffer[i] = input_buffer[i + 1];
    }
    input_pos--;
    cursor_pos--;
    input_buffer[input_pos] = '\0';
    redraw_input_line();
}

void handle_input_char(char c) {
    if (c == '\n' || c == '\r') {
        putchar('\n');
        input_buffer[input_pos] = '\0';
        snek_eval_line(input_buffer);
        input_pos = 0;
        cursor_pos = 0;
        memset(input_buffer, 0, sizeof(input_buffer));
        display_prompt();
    } else if (c == 8 || c == 127) {
        delete_char();
    } else if (c == 0x1B) {
        // Escape key - ignored
    } else if (c == 0x82) {
        if (cursor_pos > 0) {
            cursor_pos--;
            redraw_input_line();
        }
    } else if (c == 0x83) {
        if (cursor_pos < input_pos) {
            cursor_pos++;
            redraw_input_line();
        }
    } else if (c == 0x80) {
        scroll_up();
    } else if (c == 0x81) {
        scroll_down();
    } else if (c >= 32 && c <= 126) {
        insert_char(c);
    }
}

int putchar(int c) {
    if (c == '\n') {
        cursor_x = 0;
        cursor_y++;
        if (cursor_y >= LCD_ROWS) {
            scroll_up();
        }
        return c;
    } else if (c == '\r') {
        cursor_x = 0;
        return c;
    } else if (c == 8 || c == 127) {
        if (cursor_x > 0) {
            cursor_x--;
        } else if (cursor_y > 0) {
            cursor_y--;
            cursor_x = LCD_COLS - 1;
        }
        lcdSetCursor(cursor_x * 6, cursor_y * 8);
        lcdWriteChar(' ');
        lcdSetCursor(cursor_x * 6, cursor_y * 8);
        lcdDisplay();
        return c;
    }
    lcdSetCursor(cursor_x * 6, cursor_y * 8);
    lcdWriteChar((char)c);
    cursor_x++;
    if (cursor_x >= LCD_COLS) {
        cursor_x = 0;
        cursor_y++;
        if (cursor_y >= LCD_ROWS) {
            scroll_up();
        }
    }
    lcdDisplay();
    return c;
}

void display_init(void) {
    lcdFill(0);
    lcdDisplay();
    cursor_x = 0;
    cursor_y = 0;
}

void display_clear(void) {
    lcdFill(0);
    cursor_x = 0;
    cursor_y = 0;
    lcdDisplay();
}

void display_draw(void) {
    lcdDisplay();
}

void display_putchar(char c) {
    putchar(c);
}

void keyboard_init(void) {
    // Already initialized in board_init
}

uint8_t keyboard_read(void) {
    return kbdGetChar();
}

void board_loop(void) {
    uint8_t c = keyboard_read();
    if (c) {
        handle_input_char((char)c);
        last_cursor_toggle = board_millis();
        cursor_visible = true;
    } else {
        uint32_t now = board_millis();
        if (now - last_cursor_toggle > 500) {
            cursor_visible = !cursor_visible;
            last_cursor_toggle = now;
            redraw_input_line();
        }
    }
}